Reconstructed Granite insulator

Reconstructed Granite. — This material is being used as an insulator on some electric lines in the United States. It is said to consist of choice Maine granite, pulverised, moulded into form and fused together at a temperature of 3,000 deg F. It differs in several respects from the natural stone. It is claimed that the material is not only absolutely fireproof, but that it resists the action of every known solvent, whether acid or alkali, with the exception of hydro-fluoric acid, which is said to affect it only superficially. It is stated that it has been tested in liquified air without injury, remaining as strong while frozen as before, and that, being vitrified throughout, it does not absorb moisture. Crushing tests made at the Watertown Arsenal gave results as high as 14,560 lbs. per sq. in., and its tensile strength was found to be from 480 to 500 lbs. per sq. in. It has not only been used for section insulators but also for cup insulators, and a recent test at Niagara Falls showed that it required 56,600 volts to penetrate through half-an-inch of this material.